01. Background Introduction
In automated production lines of industries such as lithium batteries and photovoltaics, material loading and unloading mechanisms are frequently used to complete the tasks of loading and unloading materials. There are many ways to implement loading and unloading mechanisms, the most common being: multi-axis robots, SCARA robots, and multi-axis CNC loading and unloading modules.
Several types of loading and unloading equipment (mechanisms) each have their own advantages and disadvantages. Below is a detailed introduction to the 4-axis CNC loading and unloading module developed by MOONS.
02. Equipment Introduction
The 1-axis and 4-axis CNC loading/unloading module has four axes: X, Y, Z, and T. The X, Y, and Z axes can perform linear, circular, and other interpolation movements, while the T axis serves as an additional rotary axis that works in conjunction with the X, Y, and Z axes. The T axis can be equipped with a gripper to pick up materials and perform tasks such as loading, transferring materials between workstations, and unloading between multiple workstations.
2. Each of the four axes is driven by an M3 absolute encoder motor. Each axis is equipped with two safety limit switches, which are directly connected to the M3 driver, saving I/O points. The two grippers are controlled by vacuum pressure solenoid valves, and the two vacuum pressure arrival signals are fed back by switch signals.
3D schematic diagram of 4-axis CNC loading and unloading module
The process flow is as follows:
Under the scheduling instructions of the human-computer interaction host computer, the 4-axis gripper picks up materials and completes the process flow such as loading, vision photography, transfer between the A, B, C, and D process processing stations, buffering at station H, and unloading between the above 8 stations.
Workstation diagram
8 workstations
Station G (Loading Station), Station A (Process 1), Station B (Process 2), Station C (Process 3), Station D (Process 4), Station H (Process Flow Buffer), Station E (Visual Inspection), Station F (Unloading Station)
03. Control Scheme
Topology diagram:
Performance indicators
1. Position accuracy: ±0.01mm
2. Speed: 800mm/s
3. Maximum load: 15kg
Technical difficulties
Compared to robotic loading and unloading mechanisms, multi-axis CNC loading and unloading modules generally produce more noise and vibrate more during start-up and shutdown. To address these noise and vibration issues, we have adopted the following measures, perfectly resolving the problem and achieving almost the same performance as a robot at a lower cost:
• Employs a precision, low-noise electric cylinder to effectively reduce operating noise;
• Optimize M3 servo drive parameters to reduce jitter during start-up and shutdown;
• Optimize the controller's motion control parameters to improve the smoothness of operation.
Solution advantages
1. The entire system utilizes Anpu Mingzhi's product series: controllers, drivers, and servo motors, providing one-stop service and shortening the development cycle;
2. The overall cost is about 40% lower than that of a robot, while the operating speed and positional accuracy are basically the same.
3. The control system offers diverse communication methods to meet common communication requirements;
4. The motion trajectory is programmed using G-code, making it a universal and convenient tool;
5. The human-computer interaction host computer interface is user-friendly, and parameter setting, equipment operation, debugging and teaching are convenient and flexible.
